Chain type loom shedding mechanism

ABSTRACT

A chain type shedding mechanism for a loom and characterized in that pattern forming members are in the form of profiled chainlike links adapted to be removably connected to form endless pattern control chains, said links being connectable in any desired manner to enable any desired sequence of movement or lack of movement of a heald frame. The links are profiled to cause motion of the heald shaft having an accurately profiled peripheral surface in accordance with a displacement curve of any known form to produce controlled finite acceleration to a cooperating follower member.

United States Patent [19] 1111 3,763,897 Griffith Oct. 9, 1973 [54] g zg 'gg fi LOOM SHEDDING FOREIGN PATENTS OR APPLICATIONS 12,950 1895 Great Britain 139/78 [75] Inventor: John Dalton Griffith, Littleover,

England OTHER PUBLICATIONS [73] Assignee: Bones Machine Company Limited, 92? Ge m?" RPH F VQF St ff d h' E l d a or s an Primary Examiner-James Kee Chi Filed? 1972 Attorney-James E. Nilles [211 App]. No.: 230,317

[57] ABSTRACT [30] Foreign Application priority Data A chain type shedding mechanism for a loom and Mar 2 1971 Great Britain 5 836/71 characterlzed In that pattern forming members are In i the form of profiled chain-like links adapted to be re- [52] U S 139/78 139/329 139/333 movably connected to form endless pattern control [51] 1111 01 130 '13l00 D63: 15/00 chains, said links being connectable in any desired [58] Fie'ld 'g 139/7 79 82 57 manner to enable any desired sequence of movement 13965 or lack of movement of a heald frame. The links are I profiled to cause motion of the heald shaft having an [56] References Cited accurately profiled peripheral surface in accordance Y with a displacement curve of any known form to pro- UNITED STATES PATENTS duce controlled finite acceleration to a cooperating 889,97! 6/1908 Salisbury l39/78 X f ll w r member, 2,935,093 5/1960 Morosini... 139/78 UX 3,603,351 9 1971 Piazzolla 139 79 6 Claims, 7 Drawing Flgures 'Q TmA Q -I F 0& i q 4 ll.

PATENTEU [ET 9 I975 SHEF CUP 2 CHAIN TYPE LGOM SI-IEDDING MECHANISM This invention concerns a heald shaft control means I or chain type shedding mechanism for a loom, and in particular though not exclusively control means for a high speed narrow fabric loom.

It is known in some loom constructions for the heald shaft movement or shedding mechanism to be controlled from accurately profile cams, via operating levers, according to the lifting sequence necessary to achieve the desired weaving pattern. One disadvantage of such a control means lies in the fact that cams can provide only limited pattern repeatability determined mainly by the functional limits to their size. It is also known to control heald shaft movement by providing endless chain-like members upon which are removably mounted'projecting elements suitably spaced along its length and which intermittently engage the heald shaft operatingmeans at the required moment of time in the weaving pattern cycle to cause the desired movement of the heald shaft. The use of chain-like members enables longer pattern repeats to be obtained, but this construction is not suited to high operating speeds of looms, where carefully controlled accelerations of the moving parts must be provided for since the projecting elements being spaced-apart do not generate controlled finite acceleration and thus do not generate smooth operation of the heald shaft operating levers. 7

It is an object of this invention to provide a heald shaft control means or shedding mechanism-for a loom by'means of which not only is it possible successfullyto operate at the very high speeds demanded .by presentday looms but also to enable long pattern repeats to be achieved when desired.

According to the present invention there is provided a heald shaft control means or loom shedding mechanism characterised in that pattern forming members are in the form of profiled chain-like links adapted to be 'removably connected to form endless pattern control chains, said links being connectable in any desired manner to enable any desired sequence of movement or lack of movement of a heald frame to be achieved,

I the links profiled to cause motion of the heald shaft having an accurately profiled peripheral surface in accordance with a displacement curve of any known form to produce controlled finite acceleration to a cooperating follower member.

The invention will now be described by way of example only, with reference to the drawings accompanying the provisional specification in which: 7

quiredmovement of a co-operating follower member,

for example a roller 13 which forms part of aheald shaft operating means or loom shedding mechanism such as is for example disclosed in our co-pending British Patent application Ser. No: 5836/7l filed on Mar.

The form of the links 10 is dependent upon the action that they are required to control and in the. case in which a dwell period for the heald shaft is required in either an upper shed or a lower shed position the appropriate links 10 (in the arrangement as shown) is one having an outer profile or cam edge 14 of true radius of either of two suitable proportions, the radius being a heald shaftoperating means which operates in the opposed sense.

Each link 10 is further provided with end portions 15 of substantially circular shape of radius R adapted to co-operate closely with a correspondingly shaped face .16 spaced around the periphery of a driving sprocket 17 mounted upon driving shaft 18 journalled in the loom frame 19 and driven at an appropriate speed from the loom frame 19 and driven at an appropriate speed from the loom main shaft (not shown). Thus, rotation of the driving sprocket l7 will cause a chain formed from links 10 to be driven continuously past the cooperating follower member 13 and the links 10 will be held maintained in close timed relationship with the driving shaft 18 even if operating wear has occured at FIG. 1 is a schematic sideelevation of a loom includ- FIG. 5 is a plan view of a preferred manner of connecting chain-like links together, and

FIGS. 6 and;7 are plan views ofalternativeways in which chain-like links may be connected together.

As shown in the drawings, there are-provided chainlike links 10 arranged to be joined together to form an endless articulated chain by means, forexample, of shaped pins 12. The chain-like links l0'are arranged to perform as a pattern-forming means by causing a. re-

the points of articulation of the links 10 or in the pins 12.

In the preferred arrangement shown in FIG. 5 a chain is formed from a series of pairs of links 10 each link being of thin laminae form, as shown the links 10 are assembled in staggered formation on the pins 12. That is to say the two links 10 of one pair have one link 10 ofthe next pair between them and the other link of that pair at one side of the first pair. This construction of chain effectively provides four rows of laminae and each of these rows is provided with a driving sprocket 17 on the driving shaft 18 and further provided with additional side support sprockets 17A which can conveniently be replicas of driving sprockets 17. Each sprocket 17, 17A is arranged to be mounted on driving shaft 18 such that the rotational phased relationship of the shaped areas 16 of adjacent sprockets 17, 17A is the equivalent of one chain pitch p". This arrangement of sprockets 17, 17A provides lateral support to the links 10 as they pass the co-operating follower member 13.

It is desirable that, as shown in FIG. 2, the proportions of the links 10 are such that the line of action L" passing through the centre of the follower member 13 .and the point of contact between the follower member 13 and the profile 11 when continued shall pass intermediate of the centres of radius "R" at each end por- .tion 15 of the link 10. With such arrangement the refollower member 13 will ensure correct seating of the link within the shaped area 16 of the driving sprocket 17, whereas if the line of action L when continued were to pass beyond the centre of radius R" then it would be possible for the link 10 to be tipped-up by rotation about radius R within the shaped area 16.

It is further desirable to provide each link 10 with an inner profile 20 of shape substantially as shown in FIG. 2, that is to say with relieved regions 21 arranged such that as the continuous length of chain passes from a freely suspended attitude onto the driving sprocket l7 and in the event of there being a slight lateral malalignment between links 10 and driving sprockets 17, then the first point on the sprocket 17 with which contact is made by the chain-link is the extreme outside diameter 23 of the sprocket teeth which are provided with suitably chamfered side faces 24 to cause the malaligned link 10 to be deflected slightly into true engagement position. These chamfered side faces 24 are easily produced during manufacture of driving sprocket 17 by, for example, a turning operation.

It is convenient for the articulated links 10 to be contained wholly within the loom frame 19 suspended from driving sprockets 17 as shown in H6. 1 thereby providing a suitable enclosure within which to retain any lubricant used upon the associated parts and an assembly of articulated links 10 sufficient to permit of a weaving pattern repeating in say 50 picks can be contained in such manner. A rearward extension 25 of the loom frame 19 may be provided for accommodating a chain of links 10 of greater assembled length than that required for a weaving pattern having a repeat of more than say fifty picks.

As shown in H68. 6 and 7, alternative arrangements are possible for the production of a chain of links 10.

As shown in FIG. 6 pairs of links 10 may alternate with single links 10 to form a chain having in effect three rows of laminae. As can be seen from FIG. 7single links 10 may be joined together to provide a chain having in effect two rows of laminae.

I claim:

1. A loom shedding mechanism comprising: a follower member; an endless articulated pattern control chain cooperating with said follower member; and a driving sprocket for said chain; said chain comprising pattern forming members in the form of profiled chain links adapted to be removably connected to form said endless articulated pattern control chain, and being formed from laminae arranged to be assembled in staggered formation, said links being provided with end portions of part circular shape thereby closely to cooperate with correspondingly shaped regions spaced around the periphery of said driving sprocket, said links being connectable in any desired sequence to provide an desired shedding motion, including dwell periods, and said profiled chain links being provided on a peripheral surface of said links and formed in accordance with a displacemene curve of any known form to produce controlled finite acceleration to said cooperating follower member.

2. A loom shedding mechanism as claimed in claim 1 in which the articulated chain links are supported laterally while on said driving sprocket.

3. A loom shedding as claimed in claim 1 in which said articulated chain links are proportioned such that a line of connection passing through the center of a follower member and its point of contact with a cooperating profiled portion of a chain link when extended, passes intermediate the centers of radii of the part circular end portions of the chain link.

4. A loom shedding mechanism as claimed in claim 1 in which the chain links are provided with inner profiles including a pair of relieved regions disposed so as, in use, to cause the chain link to be guided on to a cooperating driving sprocket and to correct any lateral mal-alignment of the link with the sprocket as the link passes from a truly suspended attitude on to the sprocket.

5. A loom shedding mechanism as claimed in claim 2 in which the driving sprocket is provided with a chamfered periphery.

6. A loom shedding mechanism as claimed in claim 1 in which the articulated chain links are contained wholly within a loom frame. 

1. A loom shedding mechanism comprising: a follower member; an endless articulated pattern control chain cooperating with said follower member; and a driving sprocket for said chain; said chain comprising pattern forming members in the form of profiled chain links adapted to be removably connected to form said endless articulated pattern control chain, and being formed from laminae arranged to be assembled in staggered formation, said links being provided with end portions of part circular shape thereby closely to cooperate with correspondingly shaped regions spaced around the periphery of said driving sprocket, said links being connectable in any desired sequence to provide an desired shedding motion, including dwell periods, and said profiled chain links being provided on a peripheral surface of said links and formed in accordance with a displacemene curve of any known form to produce controlled finite acceleration to said cooperating follower member.
 2. A loom shedding mechanism as claimed in claim 1 in which the articulated chain links are supported laterally while on said driving sprocket.
 3. A loom shedding as claimed in claim 1 in which said articulated chain links are proportioned such that a line of connection passing through the center of a follower member and its point of contact with a cooperating profiled portion of a chain link when extended, passes intermediate the centers of radii of the part circular end portions of the chain link.
 4. A loom shedding mechanism as claimed in claim 1 in which the chain links are provided with inner profiles including a pair of relieved regions disposed so as, in use, to cause the chain link to be guided on to a cooperating driving sprocket and to correct any lateral mal-alignment of the link with the sprocket as the link passes from a truly suspendEd attitude on to the sprocket.
 5. A loom shedding mechanism as claimed in claim 2 in which the driving sprocket is provided with a chamfered periphery.
 6. A loom shedding mechanism as claimed in claim 1 in which the articulated chain links are contained wholly within a loom frame. 